Hydrocarbons in earth formations, such as reservoirs, are subject to the migration of fluids (oil, water, gas, etc.) over time. Detecting and measuring the movement of these fluids may be useful for estimating the producible hydrocarbon content of an earth formation and improving hydrocarbon recovery. The hydrocarbon movement may also be used to estimate the rate of depletion of a reservoir. One way of estimating hydrocarbon movement may be through the use of gravity measurements. However, the use of gravity measurement may be limited by various factors, including, but not limited to, availability of suitable tools and the expensive nature of gravimeters, which may cost tens of thousands of dollars.